I have users who frequently copy and paste between presentations to create new ones. We have a corporate template with a set of slide masters, and when he copies the slides it also copies in the masters. After doing this a few times it creates a monster presentation.

I've tried a number of ways to copy and paste slides into the presentation, including using the New Slide, Insert Slides from Other Presentation and the Copy, Paste, Use Destination Theme. While it may not copy over a whole new set of masters, it still adds additional slides in the overall slide master.

I know I can go in and delete the extra masters in slide master view, but most of my users won't do that due to time or skill. Is there a way I can teach them to copy over slides without dragging masters for PowerPoint 2007?